4 meters and the frequency is 3 hz what’s the wave speed

When an object moves in uniform circular motion, the direction of its acceleration is a) in the same direction as its velocity vector. b) in the opposite direction of its velocity vector c) is directed toward the center of its circular path. d) is directed away from the center of its circular path. e) depends on the speed of the object.

Argon, neon, and xenon are examples of

Give one example to show that when substances are mixed, it may result in a chemical or a physical change depending on the conditions.